Synthesis and Characterization of Nanostructured Undoped/Doped CuO Films and their Application in Photoelectrochemical Water Splitting

Abstract:Metal oxide semiconductors are the most promising materials for photoelectrochemical production of hydrogen on account of a) easy availability, b) low cost, c) simple preparation methods and d) stability. The nanostructured metal oxides are in great demand due to high surface to volume ratio and enhanced surface effects for their high-tech applications. The authors are involved in such studies and have worked on doped and undoped Fe2O3 and CuO. CuO on account of favourable bandgap (1.4 eV) absorbs throughout the visib le region and is considered to be a material of choice as photoelectrode in PEC cell. The samples of undoped and (Cr/Fe) doped CuO were prepared using spray-pyrolysis technique. XRD analysis revealed the exclusive formation of CuO phase. Good adherence of films with substrate was confirmed by scotch tape method. The SEM analysis confirmed the granular surface of the film. Scherrer’s calculation indicated the average grain size of the order of ~87 nm. Film samples were then converted into photoelectrodes by generating ohmic contact and photoelectrochemical behaviour was studied at pH 11 and 13 in NaOH. Enhanced photocurrent generation was observed in the sintered samples and also with the increase of electrolyte pH from 11 to 13, irrespective of nature and amount of dopant. However the variation in dopant concentration revealed a variable trend in the photocurrent generation. Detailed results would be discussed on the PEC studies on nanostructured Cr/Fe doped (0.5, 1 & 2 at.%) copper oxide films (unsintered and sintered at 5000C in air for 5 h.), not so far studied and reported in the literature.